This invention relates to a silicon layer solar cell and a method of producing it.
Silicon solar cells designed to convert the sun's energy into electricity are becoming increasingly important technologically. Any further reduction in manufacturing costs will extend the range of application of silicon solar cells still further.
One decisive step towards reducing manufacturing costs is the polycrystalline silicon solar cell. With the polycrystalline silicon solar cell, costs of the silicon raw material can be reduced substantially. Since only an approximately 100 microns thick polycrystalline silicon layer is required for electrical operation of the silicon solar cell, it is possible to apply this approximately 100 microns thick silicon layer to a suitable substrate and to manufacture a silicon solar cell in a manner known per se in this way. Tests with silicon layers on stainless steel substrates are known from "Material Engineering", October 1979, page 6 and tests using silicon layers on carbon are known from "VDI-Nachrichten", No. 34, Aug. 22, 1980, page 6. It is also possible to use substrates comprising very low resistance silicon (produced by normal metallurgical techniques for producing solid metal). Unfortunately, metallurgical silicon has two disadvantages as a substrate material: it can only be formed into substrates at substantially high costs (as compared to carbon or metals, for example) and it usually contains shrinkage cavities which are highly disruptive.